Granular material sprayer



May 24, 1966 w, coy 3,252,658

GRANULAR MATERIAL SPRAYER Filed June 15, 1964 INVENTOR WALTER G. CoY

United States Patent 3,252,658 GRANULAR MATERIAL SPRAYER Walter G. Coy, 17604 Stansbury, Detroit, Mich. Filed June 15, 1964, Ser. No. 375,033 5 Claims. (Cl. 239-335) This invention relates to improvements in spreader equipment and more particularly has reference to a portable apparatus for dispensing granular material and the like in a fluid medium such as air.

Various processes are now in commercial use, wherein granular materials such as powders, chips and the like, are combined with a fluid medium such as air and dispersed through a nozzle or other suitable outlet. Examples of processes in which such means are employed include paint or flock spraying, salt spreading, chip surfacing of floors, the prevention of offsetting on printing presses, asphalt coating of roofs, and various other similar applications.

In these processes, the granular material is usually fed into a high pressure air line and carried with it through the oulet nozzle and onto the surface to be coated. It is normally highly desirable that the spray emitted from such apparatus contain a uniform distribution of the granular material throughout the fluid medium. Although such uniform dispersion can frequently be at tained by proper mixing of the powder with the compressed air prior to issuance from the outlet nozzle, the high pressure spray emitted disturbs the uniformity of the dispersion as it is settling upon the surface to-be coated. The resulting nonuniform coating is often unsatisfactory and the operator accordingly must repeat the operation until the entire surface to be coated has been sufficiently covered with the coating material. Even with such repeated passes of the coating apparatus, it is often impossible to attain the uniform coating desired.

Previous attempts to provide a more uniform spray have been directed towards rnore efficient and thorough mixing of the solid and fluid components of the spray. However, this uniformity has been always lost or impaired after issuance from the nozzle due to the effect of the high pressure stream on the dispersion pattern as the spray settles upon the surface to be coated.

In recognizing the intensity of the air stream exiting from the nozzle as the cause of non-uniform dispersions, rather than the thoroughness of the gas-powder mixing prior to spraying, I have provided apparatus for produc ing a highly uniform coating upon the sprayed surface. In general, this is accomplished by providing apparatus which produces a low pressure cloud or spray carrying the granular material and thereby permits settling of the spray upon the sprayed surface with no appreciable impairment of the dispersion pattern after issuance from the outlet nozzle.

It is therefore the primary object of the present invention to provide spraying apparatus which permits thorough mixing of the solid and gaseous components of the spray, and permits highly uniform spraying of the mixture upon the surface to be coated.

Another object is to provide apparatus of this kind which produces the spray in the form of a low-pressure cloud.

Another object is to provide apparatus of this kind which is extremely simple in construction, reliable in operation, and low in cost.

Other objects and advantages will be more readily apparent from the following detailed description of a preferred embodiment of the present invention. The description makes reference to the drawing in which:

FIG. I is an elevational view taken partly in crosssection of a preferred embodiment of the present invention,

Patented May 24, 1966 FIG. 2 is a cross-sectional view taken through the valve assembly of FIG. 1 and enlarged somewhat for purposes of clarity,

FIG. 3 is a fragmentary cross-sectional view taken substantially on line 33 of FIG. 1.

Referring to the drawing in detail, FIGS. 1-3 show a preferred embodiment of the present invention as generally comprising a gravity feed hopper 10, a tube or conduit 12, and an air feed 14.

The gravity feed hopper 10 comprises a cylindrical container 16 having an upper open end 18, and a tapered neck 20 at its lower end terimnating in a tubular outlet or spout 22.

The tube 12 includes an elongated horizontal central portion 24 having an upwardly extending intake section 26 at its rearward end, and a nozzle section 28 at its forward end. The spout 22 of the hopper 10 fits within the upper open end of the intake section 26 0f the tube 12 and is releasably secured therein by means of a releasable clamp 30 having a tightening screw 32 adapted to tighten an annular bracket 34 about the intake 26.

The intake portion 26 of the tube 12 is curvate at its lower section where it joins the central portion 24. A screen 36 fits across an opening 37 provided in the central portion 24 immediately forward of this curved section.

The air feed 14 comprises an air intake line 38 connected to a suitable source of compressed air (not shown), a pressure regulator 40 mounted along the line 38, a control valve 42 mounted forward of the regulator 40, and an orifice member 44 connected to the air intake line 38 forward of the valve 42 and extending into the interior of the central portion 24 of the tube 12.

The pressure regulator 46 is ofthe conventional variety having an adjusting screw 46 for manual adjustment of the pressure in the line 38. The control valve 42 is a conventional normally closed valve assembly as can best be seen in FIG. 2, mounted along a sleeve 48 which has an interior passage 49 and is disposed at the forward end of the air line 38. The valve 42 comprises a valve disc 50 mounted across an aperture 51 in the interior passage 49 of the sleeve 48 at the end of a valve rod 52 which extends slidingly through an opening 53 in one side of the sleeve 48. A coil spring 54 extends between the valve disc 50 and the opposing interior face of the passage 49, and normally biases the valve disc 50, which 7 has outer dimensions exceeding those of the aperture 51,

in sealing position across the aperture 51 so as to prevent the passage of air therethrough. By pressing on the cap 56 at the outer end of the rod 52 against the force of spring 54 the disc 50 is moved away from sealing engagement with the aperture 51, thus permitting air to flow through the sleeve 48 to the air line 38 and thence to the orifice member 44.

It is apparent that the spring 54 could be eliminated if desired in the valve 42 since the pressure in the passage 49 acting on the face of the valve disc 50 would tend to urge the disc 50 toward a closed position.

The orifice member 44 comprises a cylindrical block 58 projecting partially through an opening along the lower face of the central portion 24 of the tube 12. An inlet passage 60 is provided in the portion of the block 58 dispose-d exteriorly of the tube 12 and is connected in fluid-tight manner with the air line 38 so as to receive air therefrom. A vertical passage 62 extends axially in the cylindrical block 58 from the forward end of the passage 60 to a point in the portion of the block disposed interiorly of the tube ,12. An outlet passage 64 extends horizontally from the upper end of axial passage 62 to the forward exterior face of the block 58. Air is thus carried from the air line 38 through the passages 60, 62 and 64, to the interior of the central portion 24 of the tube 12 and issues from the orifice member 44 directed towards the nozzle section 28.

In operation, the granular material 66 to be sprayed is placed in the hopper through its upper opening 18. As shown in FIG. 1, this material 66 falls under the influence of gravity through the spout 22 and intake portion 26 of the tube 12 to a point forward of the screen 36. Compressed air is fed from the source (not shown) through the air intake line 38, past theregulator 40, and is stopped at the normally closed valve 42. When the valve 42 is manually opened by depressing the rod 52 and cap 56 the compressed air passes through the valve and enters the orifice member 44. The air passes through passages 60, 62 and 64 and into the interior of the central portion 24 of tube 1-2 where it is directed towards the nozzle section 28.

As the compressed air moves out of the orifice member 44 towards the nozzle section 28, it acts in the same manner as air flowing in a Venturi (i.e. according to the Bernoulli theory) and creates a low pressure zone immediately adjacent the orifice member 44. This low pressure is communicated rearwardly along the tube 12 to the granular material 66 and the screen 36. This pressure is lower than atmospheric pressure and hence causes outside air to be sucked in through the screen 36; the fast-moving stream of high pressure air issuing from the orifice 44 will pull this incoming air in the forw-arddirection along the tube 12 towards the nozzle 28. Air will also be sucked in between the granular particles 66 in the hopper 10 through the opening 18 at the top of the container 16.

These movement of air will be movements of relatively large volumes of air due to the size of the screen 36 and the opening 18. The air will move at a relatively slow velocity (due to its volume) in the forward direction along the tube 10 toward the nozzle 28 and will carry particles of granular material 66 with it in suspension. This slow-moving large volume of air and particles will emerge from the nozzle 28, which is flared as shown in FIG. 3, in the form of a slow moving cloud or spray which will settle upon the surface to be coated.

The low velocity of the issuing spray will prevent impairment of its uniform pattern of dispersion as it settles upon the treated surface. That is, the distribution of the granular particles 66 in the air mass as it passes through the nozzle 28 wil not be disturbed by subsequently issuing air volumes but will settle upon the coated surface with substantially the same distribution as when it issues from' the tube 10.

The result of this substantially undisturbed pattern of dispersion is a more uniform coating than can be obtained by conventional spraying equipment.

If desired, a butterfly valve 68 may be mounted in the central portion 24 of the tube 12 between the screen 3 6 and the orifice member 44, as shown in FIG. 1. This valve 68 may be opened manually and serves to control the amount of granular material 66 and the volume of air that will be emitted from the apparatus.

It can be seen that the present apparatus maybe used to spray any type of granular material such as powder, chips, or other dry solid particles. It can also be used in conjunction with other fluids such as liquids, mixing the dry material with the liquid and emitting them in the form of a liquid spray. In such a case, liquid is provided through the screen 36, the air discharged into the nozzle 28 from the line 38 drawing the mixed liquid and granular material through the nozzle 28 to form a soft spray or cloud.

It will be apparent to those skilled in the art to which this invention pertains that various changes and modifications may be made without departing from the spirit of the invention as expressed by the scope of the appended claims.

I claim: :1. A device for sprayinggranular material and the like, comprising (a) an elongated tube having a straight main portion terminating at one end in a nozzle outlet and at the other end in an upstanding intake section,

(b) a hopper for said material and mounted on said upstanding intake section for delivering the material thereto by gravity,

(0) fluid injection means in said tube for introducing a stream of pressurized fluid directed towards said nozzle outlet and located at a point approximately one third the distance from the intake section to the nozzle outlet, whereby to create a suction upstream of the injection means,

(d) a fluid intake provided in said tube intermediate said injection means and said intake section whereby the suction produced by the injection means draws fluid from said fluid intake and material from said intake section to be mixed within said tube and expelled from said nozzle outlet in relatively high volume but at relatively low velocity.

2. The device as defined in claim 1 and in which said fluid intake is disposed approximately medially intermediatesaid injection means and said intake section whereby mixing of said materal and said fluid from the fluid intake begins to occur upstream of said injection means.

3. The device as defined in claim 1 and including a valve in said tube intermediate said fluid intake and said injection means.

4. The device as defined in claim 1 and in which said fluid intake comprises an opening in the wall of said tube on the upper side thereof.

5. The device as defined in claim 1 and in which an upstanding intake section is approximately one-sixth the length of said main tube portion.

References Cited by the Examiner vUNITED STATES PATENTS 1,849,945 3/1932 Mobley et a1. 239428 1,894,879 1/1933 Lay 239--428 2,699,403 1/ 1955 Courts 239335 2,737,417 3/1956 Gundersen 239377 2,887,274 5/1959 Swenson 239-376 2,934,241 4/1960 Akesson 239-336 2,991,944 7/1961 Sullivan 239335 3,109,594 11/1963 'Pletcher 239-424 FOREIGN PATENTS 323,253 9/ 1957 Switzerland.

M. HENSO-N WOOD, JR., Primary Examiner.

R. STROBEL, Assistant Examiner. 

1. A DEVICE FOR SPRAYING GRANULAR MATERIAL AND THE LIKE, COMPRISING (A) AN ELONGATED TUBE HAVING A STRAIGHT MAIN PORTION TERMINATING AT ONE END IN A NOZZLE OUTLET AND AT THE OTHER END IN AN UPSTANDING INTAKE SECTION, (B) A HOPPER FOR SAID MATERIAL AND MOUNTED ON SAID UPSTANDING INTAKE SECTION FOR DELIVERING THE MATERIAL THERETO BY GRAVITY, (C) FLUID INJECTION MEANS IN SAID TUBE FOR INTRODUCING A STREAM OF PRESSURIZED FLUID DIRECTED TOWARDS SAID NOZZLE OUTLET AND LOCATED AT A POINT APPROXIMATELY ONE THIRD THE DISTANCE FROM THE INTAKE SECTION TO BE NOZZLE OUTLET, WHEREBY TO CREATE A SUCTION UPSTREAM OF THE INJECTION MEANS, 